This photo taken May 12, 2012 in Paris shows an illustration made with figurines set up in front of Facebook's homepage. / JOEL SAGET AFP/Getty Images

by Matt Krantz, USA TODAY

by Matt Krantz, USA TODAY

Facebook (FB) starts trading today as the newest member of the much-watched Nasdaq 100 index, leading investors to wonder if shares will get a further lift as a result.

In afternoon trading, Facebook shares were down 1.4% to $27.60.

The No. 1 social networking stock is the latest addition to the Nasdaq 100, which is a collection of the 100 most-valuable non-financial stocks that trade on the Nasdaq. Investors found out last week the stock was being added to the index to replace outsourcing firm Infosys, which is moving to the New York Stock Exchange.

Investors are wondering whether the addition to the index might generate additional buying of the stock since mutual funds and exchange-traded funds that mirror the Nasdaq 100 will need to buy shares. The Nasdaq 100 is the benchmark for 7,100 investment products worldwide with an invested value of $1 trillion, Nasdaq says. That's a significant pool of buying considering Facebook has a market value of $60 billion.

The addition to the Nasdaq 100 also comes at a fortunate time for Facebook. Shares of the company, which went public in May 2012 at $38 a share, have been recovering since hitting their low of $17.73 on Sept. 4. At Tuesday's close of $27.57, Facebook shares are 27% below their IPO price and 57% above their low.

Investors are encouraged with the company's progress making money off mobile users and the stock has been upgraded by analysts since falling more than 50% from the IPO price.

Additionally, many observers who assumed Facebook's stock would collapse following large unlocking of shares that allowed employees to sell, have been wrong. Facebook's shares have largely rallied, including following a massive Nov. 14 unlock that freed up 777 million shares to be sold.

While just being added to the Nasdaq 100 alone isn't likely to be a big driver for the stock, the upward momentum of Facebook shares continues to lure investors and any good news adds to that, says Francis Gaskins of IPO Desktop Premium. "With any stock able to recover like that, many people will get interested," he says. Being added to the Nasdaq 100, "is not critical, but a plus."